[email protected] (Niels Möller) writes:

> So I'm considering this change,
>
> diff --git a/curve25519-mul.c b/curve25519-mul.c
> index adb20cb..f5127d7 100644
> --- a/curve25519-mul.c
> +++ b/curve25519-mul.c
> @@ -72,7 +72,11 @@ curve25519_mul (uint8_t *q, const uint8_t *n, const 
> uint8_t *p)
>    itch = ecc->p.size * 12;
>    scratch = gmp_alloc_limbs (itch);
>  
> +  /* Note that 255 % GMP_NUMB_BITS == 0 isn't supported, so x1 always
> +     holds at least 256 bits. */
>    mpn_set_base256_le (x1, ecc->p.size, p, CURVE25519_SIZE);
> +  /* Clear bit 255, as required by RFC 7748. */
> +  x1[255/GMP_NUMB_BITS] &= ~((mp_limb_t) 1 << (255 % GMP_NUMB_BITS));
>  
>    /* Initialize, x2 = x1, z2 = 1 */
>    mpn_copyi (x2, x1, ecc->p.size);
>

Checked in now, together with updates of tests and docs.

Nikos Mavrogiannopoulos <[email protected]> writes:

> It would make sense to document the version of nettle after which this
> behavior is followed, and probably add some ifdef similarly to FIPS202
> for sha3.

Not done yet.

Regards,
/Niels

-- 
Niels Möller. PGP-encrypted email is preferred. Keyid C0B98E26.
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